With ten days left in the 2017 Atlantic hurricane season, there is no sign of any tropical development on the horizon. Wind shear is incredibly high in the Gulf of Mexico with a deepening trough nearby. Upper level winds are also unfavorable for tropical or subtropical organization in the Atlantic and Caribbean. Not to mention, water temperatures are cooling too. At this pace, with no areas of interest, the hyperactive 2017 Atlantic season will wrap up with 17 named storms, 10 hurricanes and 6 major hurricanes. It is the busiest Atlantic season since 2012, in terms of named storms. When we analyze the total energy output of all tropical systems during the entire hurricane season, or ACE, the number is incredibly high in 2017. According the Dr. Klotzbach and meteorologists at Colorado State University the ACE in 2017 is 226. In an average season, the ACE is 111. This makes 2017 the 5th busiest season on record in terms of ACE, according to NOAA.
A series of disturbances bring several opportunities for rain this work week to Florida. A weak surface low will swing across the Sunshine State Thursday and Friday. No tropical development is expected with this feature. Below is the GFS forecast Thursday evening.
Invest 96L is still a non tropical low near The Azores Tuesday afternoon. Upper level winds are favorable for some subtropical development through mid-work week. By late Thursday and Friday wind shear increases and subtropical development is less likely. Regardless, some squalls are expected in the central and south Azores over the next few days.
There are about 2 weeks left in the 2017 Atlantic season. Mid to late November named storms are less common as water temperatures are cooling and wind shear is elevated with active frontal boundaries. Only 38 named storms have forms in the Caribbean, and Atlantic from November 11th through November 30th since 1851. The graphic below is courtesy Google Earth.
An area of low pressure in the northeast Atlantic could gain some tropical characteristics in the days ahead. As of Monday afternoon there is a medium chance a tropical depression or Subtropical Storm Sean forms over the next 5 days. Invest 96L could impact the central or southeast Azores mid work week as it meanders in the vicinity.
Elsewhere the tropical Atlantic season winds down. Water temperatures are still in the low to mid 80s in the southwest Caribbean. The GFS keeps pressure in this region generally low over the next 5-7 days+. This is worth keeping an eye on next week.
Tropical Storm Rina continues its track northward over the open northern Atlantic Wednesday. As of 11 AM AST max sustained winds are at 60 mph as it races northward at 21 mph. The 17th named storm of the season has likely maxed out in intensity as it starts to transition to an extra-tropical low. Convection will decrease over even cooler waters Thursday. Rina will merge with a frontal boundary and lose tropical characteristics during this time.
Elsewhere, there are no areas of interest over the next 5 days. The biggest culprit for lack of tropical features is strong wind shear. On Wednesday high shear covers the Gulf, southwest Caribbean and much of the Atlantic. There is a small pocket of marginally favorable upper level winds in the northwest Caribbean. The image below is courtesy the University of Wisconsin.
November named storms are less common as the month progresses. Water temperatures are cooling and upper level winds are less conducive for tropical development with fronts on the move. 74 named storms have formed in November since 1850. Here’s a look at the named storm origin points from November 1-30th. The graphic below is courtesy Google Earth.
Rina became the 17th named storm of the active 2017 Atlantic season Monday night. Rina is still a minimal tropical storm at 10 AM AST with 40 mph winds. Despite hostile upper level winds, convection increases on the northeast side of Rina. If this continues, Rina may increase a bit in intensity over the next 24 hours. The disorganized tropical storm will transition to an extra-tropical system by Thursday morning over the cooler north Atlantic. It is no threat to land.
RIna sits over luke warm Atlantic waters Tuesday. It moves into an even cooler environment over the next 48 hours. During this time it will lose tropical characteristics. Beyond Rina, there are no areas of interest for the next 5-7 days+.
Tropical Depression 19 forms over the open north central Atlantic Monday morning. As of 5 PM AST max sustained winds are at 35 mph as it slowly moves north-northeast well east of Bermuda. The depression is disorganized as it battles some nearby dry air in the mid levels of the atmosphere. Westerly wind shear exposes the center of circulation. Tropical Depression 19 will likely become the 17th named storm of the 2017 Atlantic season, Rina, by early Tuesday morning. While gradual strengthening is expected, it will transition to an extra-tropical system over the cooler north Atlantic by Thursday afternoon. It is no threat to land, but the remnants of future Rina could bring squalls to Ireland/the United Kingdom by Friday or Saturday.
Philippe, the 16th named storm of the 2017 season, drenched South Florida Saturday and Saturday night. As of 8 AM Sunday it taps energy from a nearby cold front. While the tropical low is disorganized structurally, winds increase up to 50 mph as it races northeast at 32 mph. Tropical Storm wind gusts were felt in the Northwest Bahamas early Sunday morning. Philippe transitions to an extratropical low as it merges with a frontal boundary over the Western Atlantic over the next 24 hours. It strengthens further during this time.
The remnants of Philippe could clip or pass over coastal New England late Sunday into Monday. Winds could gust to high-end tropical storm force or even hurricane force during this time.
Hurricane Hunters found a closed low Saturday morning. Potential Tropical Cyclone 18 is upgraded to Tropical Depression 18 with 35 mph at 11 AM. Squalls drench western Cuba and a wet late Saturday and early Sunday is in the cards for South Florida and the Northwest and Central Bahamas. As of 11 AM the National Hurricane Center anticipates strengthening to Tropical Storm Philippe by Saturday evening. This will pass close to extreme Southeast Florida overnight Saturday into Sunday with winds of 45 mph. A Tropical Storm Watch is in effect for the upper Florida Keys and Southeast Florida. Wind shear will keep future Philippe a weak tropical storm. It merges with a cold front and transitions to an extra-tropical system by early Monday over the western Atlantic. A stronger area of low pressure in conjunction with that same front drenches New England late Sunday and Monday. Winds could gust up to near hurricane force near the coast.
Future Philippe brings the threat of flooding to South Florida and the Keys through early Sunday. While widespread 2-4″ of rainfall is likely, isolated areas could pick up 6-7″ of rain. Below is the RPM rainfall accumulation forecast through Sunday.
Wind gusts near tropical storm force are possible in the Florida Keys and in South Florida Saturday evening and overnight Saturday into Sunday. Below is the GFS wind gust forecast at 10 PM Saturday. Wind gusts are stronger in a severe summertime thunderstorm.
The second to last month of the 2017 Atlantic season winds down. On Saturday there are no areas of interest and no tropical cyclone development is expected over the next 5 days. A tropical wave in the western Caribbean stirs up convection near Central America. Pressure will stay general slow in this area for the next several days.
Long-range computer models have been back and forth on possible development in the western Caribbean at the end of October or early November. The 0Z Euro shows no signs of an organized area of low pressure in the southwest Caribbean through Thursday October 26th. The 06Z GFS also shows no sign of tropical depression development.
We’ll keep an eye on this region over the next 5-10 days. Looking ahead to November, tropical cyclone development is less likely, but not unheard of. Five percent of named storms form in the last month of the Atlantic season. November Climatology shows any activity typically forms in the western Caribbean and drifts northeast.
Time ran out for Invest 92L east of the Bahamas. Wind shear is on the rise Tuesday as a cold front approaches. Upper level winds are not conducive for tropical development in the days ahead as this feature merges with a frontal boundary.
No tropical development is expected for the next 5-7 days. The ECMWF shows no areas of concern through next Sunday. The long-range GFS hints that the western Caribbean is worth watching next week. It’s a ways off, but this makes with climatology.